Culvert



July 2, 1935. J. R. FREEZE ET AL CULVERT Filed Oct. '7, 1931 J VLNVENTOR.

. T e. BY flaw, w. 940E720 ATTORNE YS,

Patented July 2, 1935 UNITED STATES PATENT OFFICE 'CULVERT Jonathan R. Freeze and Ralph W. Shartle, Middletown, Ohio, assignors to The American Rolling Mill Company, Middletown, Ohio, a

corporation of Ohio Application October '7, 1931, Serial No. 567,461 2 Claims. (01. 137-75) Our invention relates to the manufacture of corrugated metal culverts having erosion and corrosion resisting linings, and to methods of making the same.

Corrugated steel or iron culverts (usually galvanized) are of great value in the arts because of their great strength and relatively light weight and small bulk as compared to brick, concrete or tile culverts. When subjected to excessive loads, corrugated metal culverts will distort in shape to conform best, to load conditions. This is not possible with concrete or tile culverts, and is no doubt one of the reasons which enable the use of a corrugated metal for culvert purposes.

The zone of weakness in a metal corrugated culvert is in the invert or lower section of the culvert, particularly along what may be termed the base thereof. Gravity flow of water and whatever soil, dirt or abrasive matter that it carries, is along the base of a culvert.

In U. S. Patent No. 1,652,703, dated December 13, 1927, to Allerton S. Cushman, is'shown and described a culvert having a paving of asphaltic material in the base thereof, which forms-a level floor along the base of the culvert and protects the sides ordinarily by a fairly thin film of the bitumen. Accordingto the Cushman-patent, asphalt while fluid is placed into a culvert section which is then held level while the asphalt hardens. The asphalt flows to the center of the base line of the culvert and fills the corrugations, forming a pool along the center line. This, when hard, forms a level floor in the culvert. The culvert is either dipped into molten bitumen or sprayed internally with it, in the process of manufacture, as a mode of. placing the bitumen in the culvert. Where it is desired to have the corrugations filled to an extent greater than a single collected pool in the base of the culvert will do so, there will have to be subsequent dippings or sprayings with the culvert oriented slightly at an angle.

This re-dipping or spraying and subsequent hardening is a somewhat cumbersomemethod of procedure. Also, where a series of dippings are made, the more extended corrugation filling or floor in the culvert is not smooth and round, but has one or more angles where the several coatings or fillings join.

It is an object of our invention to provide for a way of filling the corrugations of a corrugated culvert to whatever depth and to whatever width of sector of the culvert is desired, with a simpler method of application and enhanced results.

Thus it is our object to make the filling separate from the culvert and arrange to have it inserted and bound in place later. This has an advantage in practice, since it avoids the necessity of a series of treatments by filling, heating and cooling, and requires simpler equipment at the culvert factory.

We have illustrated in the drawing an example of our'invention, and will describe the same in full. In the claims that follow, we set forth the essentials making up our invention, and wehere refer to the claims without further discussion of possible variations or modifications of our invention.

In the drawing:

Figure 1 is a perspective view of a piece of molded culvert filling, showing its shape before it is placed into the culvert.

Figure 2 is a perspective, partly broken away, of a culvert according to our invention.

Figure 3 is a cross section of Figure 2.

We have illustrated a section of corrugated metal culvert at I. At 2 is illustrated a typical filling for the culvert. This is a molded product having a top surface which is smooth and cylindrical, and a bottom surface 3 which is corrugated exactly to correspond to the interior corrugations of a culvert into which it is to be placed. The lateral margins 4 may be tapered so as to avoid any abrupt shoulder when the lining is inserted in the culvert. The ends of the sections may be made smooth, to make butt joints with the fillings of adjoining sections, or may be made specially to establish a different style of joint. As a material for the lining we use preferably a fiber reinforced bituminous compound, which, when cold, is flexible and limp, and will have a shape such as shown in Fig. 1, before it is placed into the culvert.

In the simplest practice the metal sections are made up at the culve'rt factory, and the filling made up at a factory where there is proper equipment for making molding compounds and molding them. When the culverts are *to be lined or filled, the lining is inserted in place, the culvert section heated externally so as to soften the contacting surface of the lining, and the outside of the culvert then cooled or permitted to cool. The result of the heating will be to bond the lining to the culvert, which will be permanent except for a reheating.

The degree of curve in cross section of the lining pieces can be as desired. If the entire interior of the culvert is to be lined, there will be two half cylinders or multiple sections of the lining used, depending on the diameter of the culvert.

A simple factory equipment can be used, such as a conveyor, a material holder to use in inserting the lining and dropping it into place with the corrugations thereon meshing with those in the culvert, and a heater over which the conveyor carries the culvert section with lining in place, and finally, a water spray for chilling the outside of the culvert to prevent dislodgment or slipping of the lining and save time in holding of the completed article until cooled down in the atmosphere.

Any convenient mode, however, of heating up the culvert section after the lining is' in place will serve.

The thickness of the filling can be controlled as desired, and tapered oil" to the sides away from the center with consequent saving of material where easy conditions of use are to be met.

With a molded top surface, it is evident that the exact type of surface, level, curve, etc., that is desired can be provided.

Our invention should be distinguished from instances where it has been suggested to mold within a pipe section some filling material, or to insert within the invert of a pipe section, some level fiow sustaining floor, which is of metal, ceramic material, or otherwise formed.

As material for the filling pieces, the chief requisites are that they be heat plastic, of high adhesiveness, and flexible at room temperature so that it will adapt itself to any particular shape of culvert to be lined. The bituminous ingredient should not be short or brittle in nature, so as to allow for contraction and expansion, and also for distortion under load of the culvert in which it is placed.

In order to insure against trapping of air between the lining and the inner culvert wall, it is advisable to shake or jar the culvert when it is being heated for bonding the lining in place. It is advantageous to heat the culvert first on its lowest part, thus allowing any entrapped air to escape up the sides before the bonding takes places. It furthermore is helpful in avoiding entrapment of air if the corrugations of the lining are made somewhat higher than would correspond to the corrugations of the metal culvert.

In spite of the cost of molding, the lining of culverts as we have described, is more economical than the former methods employed, as well as the product being one of enhanced value and greater accuracy. The only heating of the filling material sufdcient to melt it is done prior to molding. The heating of the culvert section is brief, and purposely kept down to just suificient to establish a bond with the lining. There is no necessity for re-dipping for a second filling.

While our culverts may be dipped after the lining is in place, this is not necessary. In case dipping is done, however, the molded linings will preserve their form better than the linings as provided for in the process described in said Cushman patent.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent, is:-

1. In combination, a corrugated metal culvert having therein a pre-formed initially flexible lining or bituminous material, said lining having corrugations upon one side to mate the corrugations on the inside of said culvert, and a planar wear surface upon the other side, said lining being formed of a heat plastic, flexible bituminous material, and of a width sulficient to extend partially up the sides of the culvert so as to form a trough shaped paving therein, said lining being bonded together with said culvert by the adhesive action of the bitumen thereof, under heat.

2. As an article of manufacture, a pro-formed lining strip for corrugated metal conduits, said lining strip having upon one side transverse corrugations to mate with the corrugations of standard metal conduit and having on the other a planar wear surface, said lining strip being made of bitumen and being sufiiciently flexible at normal temperatures of use to conform to the curved interior of a corrugated metal conduit, said bitumen having the characteristics of softening and becoming highly adhesive to metal at least at the corrugated surface thereof so as to permit the formation of a strong bond between said lining and said corrugated conduit by the application of heat to the exterior of said conduit when said lining is in place therein.

JONATHAN R, FREEZE.

RALPH W. SHARTLE. 

